The Promise One Breaks
by GloriousBlackout
Summary: Bucky asks Sam to promise him something important. Sam doesn't take it well.


**A/N - Another Sam and Bucky story because it's becoming clear I have a problem. I blame Marvel filming in my country despite me being too poor to take a day-trip to Edinburgh :P**

 **This can loosely fit between chapters 1 and 2 of 'The Inevitability of Caring' but should also work as a standalone. I hope you enjoy this and any feedback is appreciated!**

* * *

In the wake of Bucky being unfrozen and settling into the palace's guest suite, Sam learns three things about him.

Number one is that he swears like a sailor. This doesn't really surprise Sam considering that for all his initial assumptions about Steve, the man can fill a swear jar in a single morning if he's around people he's comfortable with. It only makes sense that when Bucky slips out of his silent-act, he too will decorate every sentence with 'shit' and 'fuck' in much the same way Riley once did, and Sam has to admit he feels nostalgic whenever he has a conversation with Bucky that goes beyond a rude greeting. He even feels the urge to record a conversation between himself, Bucky and Steve and send it to Tony to make him re-evaluate his opinions about Captain America's innocence, until it occurs to him that that isn't really an option anymore.

The second thing he learns is that Bucky rarely sleeps. In the week since his relocation from the medical bay – which with all its cacophony of beeps and bright light isn't exactly encouraging of rest to begin with – the man doesn't seem to have spent much time in his room, choosing instead to spend his nights by the window in the lounge, watching the stillness of the outside world.

Sam only knows this because sleep eludes him more often than not as well. The alien sensation of having a bed so large he feels he could get lost in it gnaws at him every time he tries to get comfortable, and he doubts he'd be able to claim an uninterrupted night's rest even if his mind wasn't plagued by the uncertainty of his circumstances. If he's lucky he'll get four hours of sleep before falling out of bed with a defeated sigh and wandering to the guest lounge to watch TV, and every time he decides on the latter he'll find Bucky sitting serenely by the window, dead to the world and drenched in the pale glow of moonlight. It's almost a shame that Sam's presence tends to disturb his reverie, for the peace in his expression as he rests against cool glass is rarely present in the daylight hours and tends to vanish as soon as Sam announces himself.

The last thing he learns, though it takes far longer for him to realise than it should, is that Bucky seems to have placed himself under house arrest. Despite T'Challa's insistence that the man is not a prisoner and is free to wander the palace and grounds along with everyone else, Sam's pretty sure that since being allocated his own room, Bucky has refused to venture beyond even the guest suite.

On a shallow level, Sam can hardly blame him. The suite is luxurious with each bedroom being bigger than his house, complete with glittering chandeliers and four-poster beds and large windows which display both Wakanda's natural beauty and its technological strength in the distant city. More than once, Sam has found himself lost in the view as the sun rises, casting distant skyscrapers and nearby lakes and forests in an orange glow while the dark outline of mountains act as a protective shield, making him feel safe in spite of the demons lurking beyond. He can see why some would be content with simply living in peace and staring out at the world, but when the entire palace is open to them - with its vast halls and library filled floor-to-ceiling with books and grounds which stretch for miles - he can't think why anyone would deny themselves such a privilege.

Well, besides one reason.

He's seen the way Bucky stares longingly at the outside world, as if willing himself to be a part of it. Had things been different, there's no doubt in Sam's mind that he'd be able to offer the man a tour of the grounds or the city and he'd be taken up on it.

So long as Bucky convinces himself that he can snap at any moment, however, Sam knows that he will continue to hide himself away from as much of the world as he can.

The notion is an uncomfortable one despite the logic behind it, and the fact that nothing he can say will change Bucky's mind doesn't help.

* * *

It's three in the morning when Sam wakes, breathless from a dream that's already slipping from his consciousness, and he rubs his eyes to rid himself of bone-deep exhaustion that sleep alone can't erase. He knows he should lie back down and try to doze for a while, but waking at this hour has become a ritual and he knows that any attempt to sleep now is pointless.

He lets five minutes pass in silence, soaking in the sensation of soft sheets and the slightly too-hot Wakandan atmosphere, before rising and grabbing his phone from the bedside table. He could grab a book from the pile he scavenged from the library, or take a shower to wash away the sheen of sweat which rests upon his entire body, but any motivation seems to have been sapped from him during the night and he simply leaves the comfort of his room, making his way towards the quiet lounge.

He isn't surprised to find Bucky sitting alone by the window, ghostly pale in the moonlight. Sam makes as little noise as possible in order to let the man's peace last just a little longer. Even when the door creaks Bucky doesn't move a muscle, and Sam creeps over to the couch on the assumption that he's finally getting some long-overdue rest. He resists the urge to remind him that there's a perfectly good bed just a few doors down – he knows what it's like to find more comfort in awkward positions than in silk sheets – but he barely has time to settle and scroll through the news on his phone before Bucky turns of his own accord.

Sam finds himself reiterating the point that the man doesn't seem to regard sleep as a basic need. That said, perhaps sleep is something that refuses to come easily considering the doctors have scheduled their attempts to fix his brain for four days' time.

Instead of their now-routine greeting of " _Morning, Terminator," "Fuck off, Birdman_ ," a crushing silence that seems to rob the breath from Sam's lungs settles over them. He's no stranger to awkward silences between himself and the once-assassin, but he can't escape the idea that Bucky's eyeing him like he's fresh prey, and the words on his screen start to blur as his attention is dragged towards the window. Bucky's still looking at him, a worried frown marring his face, and Sam's about to remark on how creepy he's being before he's beaten to the punch.

"I need to talk to you."

Ah, wonderful. Six words that never lead anywhere good.

Sam sighs and chucks his phone onto the couch cushions before wandering over and settling himself on the windowsill to face Bucky. His companion seems instantly regretful, curling in on himself as if he's just opened Pandora's box and has to deal with the fallout, and it only makes the dread that's settling in Sam's chest feel all the heavier.

"Hit me," he says, trying to keep his tone light with little success. "What's on your mind?"

Bucky smirks and it hits Sam that, considering the horrors lurking in the man's past, the answer likely isn't one he wants to hear. He's hardly ignorant – as soon as Steve finished poring over the Winter Soldier files he'd studied them intensely himself – but even so, he can only wonder at the pain that haunts someone after such experiences.

It takes a while for Bucky to speak up, and when he does his words are more hesitant than Sam expects.

"When they're trying to get all the shit out of my head, I need… if it doesn't work, or if I hurt someone, or worse, I need you to promise me something," he says, grimacing as if every word has been pried from his lips. Sam wishes he would stop there and say nothing else; wishes that he didn't have a sudden weight of expectation pressing on his shoulders. "I need you to stop me. Whatever it takes."

The unspoken heart of the issue lances through Sam's chest with a jolt and though he tries to stop it, his disbelief escapes him in a huffed laugh. He shakes his head and looks down at his knees in an attempt to block Bucky from his sight, but the other man's eyes may as well be burning his skin. "You talk to Steve about this?"

He suspects he already knows the answer, and when he looks up to see Bucky give a single shake of the head, he's not surprised. "I thought about it, but…" He stops for a beat that seems to drag on for hours, before shrugging nonchalantly as if they're simply discussing the weather. "I don't think he could do it."

Sam doesn't bother trying to hold in his laugh this time, and he makes a point to ignore Bucky's gaze trying to dig into his mind and dissect his thoughts. "What, and you think _I_ could?"

It's Bucky's turn to laugh, albeit abruptly. "I'm sure a bullet to the head will do the trick regardless of who fires it, Sam."

"That's not what I meant and you know it."

The silence that falls between them is a heavy one, and Sam thinks he would give anything to be buried among his too-soft sheets, where he doesn't have to worry about whether he'll have to murder Steve's best friend in a matter of days. Fiery rage spreads through him before he can stop it, pooling in his veins like lava, and the fact that Bucky's able to place this burden upon his shoulders so easily makes him wonder why he ever started liking the man.

He knows he's being irrational, deep down. Knows he'd want someone to promise him the same if their roles were reversed and he thought he might kill an innocent person without any control over his actions. He'd give anything for Bucky to have asked someone else though.

"I thought… I don't know what I thought," Bucky says. Sam can see his own frustration mirrored plainly on the other man's face and wonders if this is what's been preying on his mind the entire time he's been awake; if his musings by the window have been spent assessing which member of their team will be the most appropriate executioner. "I guess I thought it'd be easier for you."

"Is that what you think of me?" Sam asks, making no attempt to hide the sudden hurt from his voice. Whether his pain is deserved, he doesn't know, but he can't deny the way his heart seems to have sunk into a pit. "What, you thought I hated you so much that I'd leap at the chance to plant a bullet in your skull?"

His words leave Bucky stunned, if his furrowed brow and the way he opens and closes his mouth without speaking are any indication. A sick sense of satisfaction rushes through Sam at the sight before guilt washes it away, leaving him drained and empty.

Perhaps he shouldn't be surprised. He'd been under the assumption that he and Bucky were on the same page – that underneath all the insults and teasing and half-joking 'I hate you's' they were both approaching something like friendship – but now he's not sure what to think. He doubts he's ever given an indication that he wants Bucky gone, but considering how much the man seems to loathe himself he can't help but wonder how many of his actions have been read that way.

He's never hated Bucky. Even his dislike in the beginning was mostly childish fun on his part; an attempt to alleviate the mood when his world was falling apart.

He's not even sure he can bring himself to hate the Winter Soldier. To hate that broken creature would be like hating a dog that bites everyone it meets purely because that's all its owner ever taught it (Sam knows that's hardly an analogy Bucky will appreciate, so he keeps his mouth shut). He's been hurt by the Soldier – hell, he imagines he's lucky to be alive after their altercations – but in the end, his blame has always rested solely on Hydra. He knows that stance is hardly one shared by the rest of the world, but he knows Bucky too well now to waste his life demonising him for actions he had zero say in.

He wonders if anything he can say will convince Bucky of that much.

"Look," Bucky says eventually, and the break in the silence almost makes Sam jump. "I know it's a lot to ask. If there was a better option, I wouldn't have bothered asking. But we both know what happens when I'm… when the Soldier takes over, and I can't let anyone else get hurt. If someone dies because they tried to help me-"

Any words Bucky means to say after that get caught in his throat, and he looks away while furiously blinking away wetness from his eyes. Sam wishes there was something he could do to make all this better – to wash away countless years of torture and death from the other man's memory- but there's nothing to do besides sit there, useless. He's suddenly aware of how weary he feels after all these months of fighting and hiding from people he once called friends; he can only imagine the sheer exhaustion which must cling to Bucky every waking moment.

"I'll do it," Sam says, the words seeming so unimpressive considering the weight behind them. "But we're talking last resort here, as in you being milliseconds away from killing someone. I don't care how far gone you are; so long as there's an option that doesn't result in me stepping in, you can be damn sure we're taking it, understand?"

All tension seems to leave Bucky in a breath and Sam barely hears his whispered "Thank you."

Sam can't quite hide his horror at seeing someone so comforted by the knowledge that he is willing to kill them should necessity demand it, no matter how reluctantly. He only hopes that such a responsibility never has the chance to fall upon him.

"You need to discuss this with Steve," Sam says, and he pushes on before Bucky can protest. "I know you don't want him to deal with this, but he cares too much for you to just leave him out of it. I'm not saying he'll be able to change your mind, but I need you to at least talk to him."

It would be funny, how much Bucky resembles a stubborn child who has to admit a wrongdoing to a parent, if the situation wasn't one that sucked any trace of humour from the world. To Sam's relief, however, he gets a compliant nod before Bucky's attention is stolen away by the forests and distant towers once more. The subject seems to have been dropped what feels like hours after it was raised, though the moon doesn't seem to have sunk any lower in the sky, and though a weight still plagues Sam's every breath, he at least feels like he can breathe again.

He knows that no sleep will come to him tonight - that nightmares will likely plague him if he tries - so he simply rises to his feet and makes his way to the couch, stopping only to switch on the widescreen against the wall.

"Hey, Bucky," Sam says, surprising himself at the lack of a teasing nickname which seems to have become instinctual. He hopes this isn't a permanent adjustment – he's been working his way through a list of robotic movie characters for weeks. Bucky turns, seeming surprised at having been addressed so soon after their conversation was dropped. "Come over here. It's about time I introduced you to Monty Python."

In spite of his initial confusion, Bucky doesn't need much persuasion before he climbs off the windowsill and settles on the other side of the couch. Sam scrolls through the extensive movie database in the meantime, hesitating only for a moment before settling on 'Monty Python and the Holy Grail'. He briefly wonders if showing a film in which a character loses all of his limbs to an amputee makes him an asshole, but he imagines Bucky won't care.

(Sure enough, the Black Knight ends up being Bucky's favourite character, to the point where he later tells Sam he regrets not saying "T'is but a scratch" to Zola).

For all his hopes that sticking on something light would ease the discomfort his promise to Bucky has caused, the only one who seems to be enjoying himself is the man who's just assigned himself a death-sentence. Sam can't help the jealousy that flares within him every time Bucky laughs at a joke, seeming to get lighter every time he smiles, but he knows it's likely only to mask the fear of what the next few days will bring. He's reminded of how, in the months following Riley's death, he would overcompensate with kindness and laughter as if doing so would make him feel human again, and he knows he has no right to deny Bucky small moments of comfort considering the uncertainty that faces him.

He finds himself focusing more on Bucky than the images on the screen; sees the way he lets himself laugh without restraint; how the darkness of the room seems to have stripped the years from his face, hiding dark lines and a scruffy beard that daylight will uncover in a matter of hours.

In a few days he will have to undergo unprecedented tests to pry buried triggers from his mind, and Sam feels his blood run cold as he imagines all the ways it can go wrong.

In trying to heal Bucky, they may accidentally disturb the Winter Soldier from its sleep. Might have to face putting him down or risk civilian casualties. Sam might have to make good on his promise and fire without thinking; might have to watch a friend die by his hand and see raw grief in the face of another as Steve is forced to watch.

It hits him then that he can't do it. Regardless of what he told Bucky and the relief such a grotesque promise had wrought, he knows that when the time comes he won't be able to pull the trigger. Perhaps it won't even matter in the end and the responsibility will be pried from his hands by one of T'Challa's guards, or the Winter Soldier will tear through him like paper before he has a chance to think.

Or maybe he'll simply be left reeling, surrounded by the bodies of civilians he promised to save.

It's selfish, he knows, and perhaps if the moment demands it then instinct will force him to change his mind. For now, though, he knows he cannot bring himself to be the one to rob Steve of his best friend all over again.

Some promises were meant to be broken, after all.


End file.
